The present invention relates to a detergent composition.
Incorporating an enzyme into a detergent composition has been practiced, and, for example, JP-A 1-501486 discloses a detergent composition using two or more specific kinds of proteases. However, since enzymatic activity is lowered under the laundering condition at a low temperature, a satisfactory washing-performance cannot be obtained and this problem is particularly remarkable in protein-related dirt of soiled socks, necks, and so on. Although JP-A 62-68898 discloses a detergent composition in which enzyme is stabilized by a sulfite, this composition does not satisfactorily solve the two problems of enzyme deactivation and washing-performance at a low temperature, either.
The object of the present invention is to provide a detergent composition which is almost free from enzyme deactivation, which is excellent in detergency under laundering conditions at a lower temperature, and which is effective particularly for protein-related dirt (of) on soiled socks and other items.
The present invention provides a detergent composition comprising
(a) 15 to 40% by weight of an anionic surfactant,
(b) 0.5 to 5% by weight of a chlorine scavenger,
(c) a protease whose xcex1-keratin-hydrolyzing activity at 10xc2x0 C. is not less than 0.09xc3x9710xe2x88x923 xcexcg/mPUxc2x7min and
(d) a protease whose xcex1-keratin-hydrolyzing activity at 10xc2x0 C. is less than 0.09xc3x9710xe2x88x923 xcexcg/mPUxc2x7min,
wherein (c)+(d)=0.01 to 0.5% by weight (as powdered enzyme product), (c)/(d)=1/5 to 5/1 and [(c)+(d)]/(b)=1/100 to 1/2 (weight ratio as powdered enzyme product).
Herein, the term xe2x80x9cenzyme powderxe2x80x9d means the enzyme product powdered by lyophilizing the supernatant of the fermenter broth concentrated by ultrafiltration.
An anionic surfactant is the xe2x80x9c(a)xe2x80x9d component in the present invention. Examples of the anionic surfactant include an alkylbenzenesulfonate, an alkylsulfate, an alkylethersulfate, an olefinsulfonate, an alkanesulfonate, a fatty acid salt, an alkyl or alkenyl ether carboxylate and an xcex1-sulfofatty acid salt or an ester thereof. Among them, an alkylbenzenesulfonate whose alkyl group has 10 to 20 carbon atoms, an alkylsulfate having 8 to 18 (preferably 10 to 14) carbon atoms, an alkylethersulfate having 8 to 18 (preferably 10 to 14) carbon atoms, and a fatty acid salt being derived from palm oil or tallow and having 8 to 18 (preferably 10 to 18) carbon atoms, are preferable. The average molar number of ethylene oxide added in the alkylethersulfate is preferably 1 to 20, more preferably 1 to 10 and particularly preferably 1 to 5. As the salts, a salt of an alkaline metal such as sodium and potassium is preferable. The incorporated amount of the xe2x80x9c(a)xe2x80x9d component is 15 to 40% by weight, preferably 20 to 40% by weight, in the composition from the standpoint of detergency and foaming property.
In the present invention, in order to prevent the enzyme from being deactivated by chlorine which is present in water, a chlorine scavenger is the xe2x80x9c(b)xe2x80x9d component. Specific examples of the scavenger include an amine such as a primary amine, a secondary amine and an alkanol amine; an inorganic peroxide such as hydrogen peroxide, sodium percarbonate and sodium perborate; a reducing agent such as a sulfite. Among them, a sulfite is preferable from the standpoint of stability in the composition and enzyme-stabilizing effect in a laundering bath. From standpoint of the stability of enzyme, the xe2x80x9c(b)xe2x80x9d component is incorporated in an amount of 0.5 to 5% by weight, preferably 0.5 to 2% by weight, in the composition.
A protease, whose xcex1-keratin-hydrolyzing activity at 10xc2x0 C. is not less than 0.09xc3x9710xe2x88x923 xcexcg/mPUxc2x7min, preferably not less than 0.10xc3x9710xe2x88x923 xcexcg/mPUxc2x7min, more preferably not less than 0.12xc3x9710xe2x88x923 xcexcg/mPUxc2x7min and furthermore preferably not less than 0.13xc3x9710xe2x88x923 xcexcg/mPUxc2x7min and whose xcex1-keratin-hydrolyzing activity at 30xc2x0 C. is preferably not less than 0.40xc3x9710xe2x88x923 xcexcg/mPUxc2x7min, more preferably not less than 0.44xc3x9710xe2x88x923 xcexcg/mPUxc2x7min and furthermore preferably not less than 0.47xc3x9710xe2x88x923 xcexcg/mPUxc2x7min, is used as the xe2x80x9c(c)xe2x80x9d component in the present invention.
In addition, a protease, whose xcex1-keratin-hydrolyzing activity at 10xc2x0 C. is less than 0.09xc3x9710xe2x88x923 xcexcg/mPUxc2x7min and preferably less than 0.07xc3x9710xe2x88x923 xcexcg/mPUxc2x7min and whose xcex1-keratin-hydrolyzing activity at 30xc2x0 C. is preferably less than 0.40xc3x9710xe2x88x923 xcexcg/mPUxc2x7min, more preferably less than 0.35xc3x9710xe2x88x923 xcexcg/mPUxc2x7min, furthermore preferably less than 0.30xc3x9710xe2x88x923 xcexcg/mPUxc2x7min and particularly preferably less than 0.20xc3x9710xe2x88x923 xcexcg/mPUxc2x7min, is used as the xe2x80x9c(d)xe2x80x9d component.
Here, the xcex1-keratin-hydrolyzing activity was expressed as a soluble material (calculated as based on tyrosine) formed from xcex1-keratin for 1 minute per casein hydrolyzing activity of 1 mPU shown in the following (ii). That is, the xcex1-keratin-hydrolyzing activity was measured according to the following (i) to (iii) methods.
(i) Preparation of xcex1-keratin
A part of skin of human heel (horny layer) was cut off with a surgical knife, and, after being cut into pieces with a pair of scissors, washed with distilled water. One gram of this horny skin was suspended in 20 to 50 ml of a 50 mM Tris-HCl buffer (pH: 8.0) containing 8 M of urea and 25 mM of xcex2-mercaptoethanol, and stirred overnight. The swollen horny skin was sufficiently ground by a TEFLON HOMOGENIZER(trademark) and subjected to centrifugal separation at 30,000xc3x97g for 30 minutes. The supernatant liquid obtained by the centrifugal separation was filtered through a filter paper (No.2 supplied by Whatman International Ltd.). The filtrate underwent dialysis to a 50 mM Tris-HCl buffer (pH: 8.0) and was then subjected to centrifugal separation at 100,000xc3x97g for 2 hours. The precipitate obtained was dissolved in a 50 mM Tris-HCl buffer (pH: 8.0) containing 8 M of urea and 25 mM of xcex2-mercaptoethanol. The solution thus obtained again underwent dialysis to a 50 mM Tris-HCl buffer (pH: 8.0) and was then subjected to centrifugal separation at 100,000xc3x97g for 2 hours. After the supernatant liquid was removed, the precipitate was dissolved in a 50 mM Tris-HCl buffer (pH: 8.0) containing 8 M of urea and 25 mM of xcex2-mercaptoethanol. The solution thus obtained underwent dialysis to distilled water and was pulverized to prepare powder after lyophilizing. The powder product was used as xcex1-keratin.
(ii) Measurement of Casein-hydrolyzing Activity
After 1 ml of a 50 mM boric acid buffer (pH: 10.5) containing 1% (w/v) of casein (Hammarsten, supplied by Merck) was held at 30xc2x0 C. for 5 minutes, 0.1 ml of an enzyme solution was added and incubated at 30xc2x0 C. for 15 minutes. Next, 2 ml of a TCA solution (0.11 M trichloroacetic acid, 0.22 M sodium acetate and 0.33 M acetic acid) was added thereto. After the resulting solution was left to stand for 10 minutes at room temperature, the acid-denatured protein was eliminated by filtration and the acid-soluble peptides contained in the filtrate were quantified by the Lowry method. That is, 2.5 ml of an alkaline copper solution [a 1:1:100 (v/v) mixture of a 1%(w/v) potassium sodium tartrate aqueous solution, a 1%(w/v) copper sulfate aqueous solution, and a solution prepared by dissolving sodium carbonate in a 0.1 M sodium hydroxide aqueous solution (sodium carbonate concentration: 2% (w/v))] was added to 0.5 ml of the filtrate. After the resulting solution was kept at 30xc2x0 C. for 10 minutes, 0.25 ml of a diluted phenol reagent (obtained by 2-fold dilution of folin-ciocalteu""s phenol reagent with distilled water) was further added. Then, after the resulting solution was kept at 30xc2x0 C. for 30 minutes, the absorbance at 660 nm was measured. Meanwhile, the result, obtained by adding the enzyme solution after adding the TCA solution and being left to stand for 10 minutes at room temperature, was determined as a blank. The 100 PU of enzyme was defined as the amount of enzyme that produced acid-soluble peptides being equivalent to one micromole of L-tyrosine per minute.
(iii) Measurement of xcex1-keratin Hydrolyzing Activity
2 mg of xcex1-keratin and 0.9 ml of a 50 mM boric acid buffer (pH: 10.5) were placed in a test tube and the resultant mixture was held at 10xc2x0 C. or 30xc2x0 C. for 10 minutes. Then, 0.1 ml of a protease solution was added thereto and mixed so that the casein hydrolyzing activity shown in (ii) mentioned above was 105mPU. After being incubated for 30 minutes for calculating xcex1-keratin hydrolyzing activity at 10xc2x0 C. or for 10 minutes for calculating xcex1-keratin hydrolyzing activity at 30xc2x0 C., the reaction mixture was filtered. The solubilized peptides contained in the filtrate were quantified by the Lowry method and the xcex1-keratin hydrolyzing activity was measured.
Examples of the protease as the xe2x80x9c(c)xe2x80x9d component include a protease produced from a microorganism deposited in the National Institute of Bioscience and Human-Technology, Agency of Industrial Science and Technology, as Bacillus sp. KSM-KP 43 (FERM BP-6532), Bacillus sp. KSM-KP 1790 (FERM BP-6533), Bacillus sp. KSM-KP 9860 (FERM BP-6534) (date of original deposition: Sep. 18, 1996) and a mutant thereof as well as a protease produced from the transformant having a gene coding the enzymes. In particular, Bacillus sp. KSM-KP 43 and a mutant thereof are excellent.
Examples of the protease as (d) component include ALCALASE(copyright), SAVINASE(copyright), DURAZYM(copyright) and EVERLASE(copyright) (all supplied by Novo Nordisk A/S), PURAFECT(copyright) and MAXAPEM(copyright) (all supplied by Genencor International) and KAP (supplied by Kao Corp.). In particular, KAP 4.3 G and KAP 11.1 G are excellent.
In the present invention, from the standpoint of detergency at a low temperature, the sum of the components (c) and (d) is 0.01 to 0.5% by weight, preferably 0.02 to 0.3% by weight, as powdered enzyme product. Further, from the standpoint of detergency to dirt derived from horny skin (keratin) or sebum, the weight ratio as powdered enzyme product of the both components, i.e. (c)/(d), is 1/5 to 5/1, preferably 1/5 to 2/1, and more preferably 1/4 to 2/1. Furthermore, from the standpoint of enzyme stability in a laundering bath, [(c)+(d)]/(b)=1/100 to 1/2 and preferably 1/80 to 1/3 (weight ratio as powdered enzyme product).
It is desirable that the composition of the present invention further contains a polyoxyalkylene alkyl or alkenyl ether whose HLB (Griffin""s method) is 11.5 to 17, preferably 12 to 16, from the standpoint of enzyme stability in a laundering bath. Here, the alkyl group or the alkenyl group has favorably 10 to 18, favorably preferably 10 to 16, carbon atoms. The oxyalkylene group is preferably an oxyethylene group. The incorporated amount of the compound is 0 to 15% by weight and preferably 0.5 to 10% by weight in the composition.
Further, a percarbonate may be incorporated in the composition of the present invention to impart a bleaching effect. Although examples of the percarbonate as salt include a salt of an alkaline metal such as sodium and potassium, an ammonium salt and an alkanol amine salt, a sodium salt is preferable. Further, from the standpoint of the stability of the percarbonate, it is preferable to be a percarbonate coated with one or more compounds selected from, for example, paraffin, a (per)borate, an ethylene oxide adduct of an alcohol, polyethylene glycol and a silicic acid-based compound. In addition, in order to further promote the bleaching effect, a bleaching activator represented by the following formula (I) or (II) may be incorporated in the composition of the present invention.
Rxe2x80x94COOxe2x80x94Phxe2x80x94SO3Mxe2x80x83xe2x80x83(I)
Rxe2x80x94COOxe2x80x94Phxe2x80x94COOMxe2x80x83xe2x80x83(II)
[In the formulae, R is an alkyl or alkenyl group having 5 to 13 carbon atoms, Ph is a phenyl group and M is selected from a hydrogen atom, an alkaline metal, an alkaline earth metal and ammonium.]
In particular, it is preferable to be a bleaching activator represented by the following formula (I), in which R is an alkyl group having 11 to 13 carbon atoms and M is an alkaline metal such as sodium.
From the standpoint of bleaching effect, the composition of the present invention preferably contains 0.1 to 10% by weight, 0.5 to 5% by weight in particular, of a percarbonate and 0.1 to 5% by weight, 0.5 to 3% by weight in particular, of a bleaching activator.
In the present invention, the detergency can be further improved by use of an alkaline cellulose which is produced from analkalophilic microorganism, e.g. Bacillus sp. KSM-635 (FERM BP-1485), or a mutant thereof. This alkaline cellulase has an optimum pH value of 7 or more when carboxymethyl cellulose is used as a substrate or has a relative activity of 50% or more at a pH value of 8 or more with respect to the optimum condition. A specific example of the alkaline cellulase is KAC 500 (registered trademark) which is supplied by Kao corp. and which is an enzyme granulation product. The composition of the present invention preferably contains this alkaline cellulase in an amount of 0.001 to 5% by weight, 0.1 to 3% by weight in particular, as the enzyme granulation product containing 0.1 to 50% by weight of the powdered enzyme product.
In the present invention, besides the above-mentioned anionic surfactant and the nonionic surfactants, an amphoteric surfactant such as an amine oxide, a sulfobetaine and a carbobetaine or a cationic surfactant such as a quaternary ammonium salt may be incorporated, if necessary.
The composition of the present invention may contain a crystalline alumino-silicate such as zeolite A, X and P in order to heighten the detergency. In particular, zeolite A is preferable. The average diameter of primary particles is preferably 0.1 to 10 xcexcm and particularly preferably 0.1 to 5 xcexcm. The incorporated amount is preferably 5 to 40% by weight, more preferably 10 to 40% by weight, in the composition.
The detergent composition of the present invention may contain, for example, 0.01 to 10% by weight of an enzyme such as lipase and amylase, 1 to 50% by weight of an alkaline agent and/or an inorganic electrolyte such as a silicate, a carbonate and a sulfate, and 0.01 to 10% by weight of an antiredeposition agent such as polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone and CMC.